Comparing the Rock genre over four decades 60s-10s

Spotify has 6 playlist called the “XXs Rock Anthems” for the decades 60s, 70s, 80s, 90s, 00s, and 10s. I’m interested in how rock has evolved from the 60s to the 10s. Multiple bands have made music spanning more than one decade and I would like to investigate how their earlier work compares to their later works and whether bands have influenced each other. Moreover when large subgenres of rock started to appear and which bands were responsible. There are three main groups to compare: the early bands from the 60s and 70s, the middle 80 and 90s bands, and late 00s and 10s. So the main questions i want to answer is:

• What are the most notable changes that happened in the rock genre from the 60s to the 10s?

The use of more digital elements in music will probably increase over the years, and more subgenres are likely to have emerged over the years. I am unsure in what way the bands have influenced each other if any at all.

The tracks are all popular songs from their respective time periods but not all songs are original. Especially among the older songs are a lot of remastered versions. Another downside is the small amount of songs representing a complete decade of song releases.

Atypical bands might be bands like Queen which is known for releasing songs in a multitude of genres and bands that have released albums spanning multiple decades. Typical bands might be bands like U2 that appear in one playlist with multiple songs.

The playlists will be analyzed on multiple levels. The decades as a collective shall be used to show trends and the general characteristics of the playlists. For a more detailed comparisons I’ll search among the most popular songs per decade or for special cases that show interesting results:

The two most popular songs per decade according to the Spotify API are:

• 1960s
  • Fortunate Son - Creedance Clearwater Revival
  • Brown Eyed Girl - Van Morrison
• 1970s
  • Hotel California - 2013 Remaster
  • Rocket Man (I Think It’s Going To Be A Long, Long Time) - Elton John
• 1980s
  • Back in Black - AC/DC
  • Take on me - a-ha
• 1990s
  • Zombie - The Cranberries
  • Under the Bridge - Red Hot Chili Peppers
• 2000s
  • Can’t Stop - Red Hot Chili Peppers
  • You’re Gonna Go Far, Kid - The Offspring
• 2010s
  • Believer - Imagine Dragons
  • Do I Wanna Know? - Artic Monkeys

How many songs are in the “XXs Rock Anthems”?

The corpus has a lack of data representing the last two decades and the 90s are over-represented. Furthermore the current data might not be the best to represent the decennia since they have not yet been verified using the hit-charts of their respective decade.

Release dates and popularity

The corpus contains several remasters which can been seen as dots that don’t bear the color of the decade they are in. Clear examples can be seen on the year 2000 where several 1960s, the orange colored ones, songs are present. This explains dots showing up later than their category but two 1980s songs have been released in the before the start of their assigned decade. The popular Barracuda - Heart was released in 1977 and I Was Made For Lovin’ You - KISS in 1979.

It’s quite remarkable that there is a handful of songs each decade that have low popularity scores which they might have lost over the years but does give us insight that current popularity isn’t the only factor Spotify have looked at making these playlists.

The acousticness decreased significantly over the decades

The current data shows that over the years the acousticness has significantly decreased. From the 1980s a significant drop in acousticness can be seen in the data. The 1960s and 1970s show a wide distribution which narrows and shifts towards no acousticness at all. The 2000s seems the decade with the least acousticness as even the outliers don’t exceed 0.12 on the scale. The 2010s see the acoustic outliers returning with “Way down We Go” from KALEO as most acoustic song.

The distribution along the modes don’t seem to have a significant preference for more or less acousticness only the 1960s and 1980s show dissimilar distributions per mode. Minor songs favor more acousticsness in the 1960s and the 1980s is reversed, favoring less acousticness.

The early rock years were more valent too

The valence appears to barely have changed in the first three decades with a small drop to the last three decades.

Rock has become more energetic and louder

Comparing the energy related to loudness per decade show very similar clouds of data points. Over the decades the representation in the low loudness and energy seems to have decreased suggesting that songs have become louder and more energetic.

It should be kept in mind that the 00s and 10s playlist have the lowest amount of songs. The 1990s is the largest playlist however which has sparsity in the low energy and loudness region as well compared to the 60s and 70s so the trend seems to be that songs have high energy and loudness.

Danceability has not seen any big changes

The distribution of danceability has not seen any huge changes over the decades. It’s quite notable that a wide range of dancebility is present in the playlists. The values range from low 0.25 songs to high 0.75 songs. with a few outliers such as the 80s song Another One Bites The Dust (Remastered 2011) - Queen

Fortunate Son versus Believer

The most popular 60s song compared to the most popular 10s song. Fortunate Son - Creedance Clearwater Revival has a clear checkerboard structure with two horizontally striped bands right at the start of the song and on 1.15 minutes. These are the two episodes in the song without vocals when the electric guitar is playing the riff over the drums without any vocals. The timbre plot of Fortunate Son has no big extremes except the short silence at the start and a vague band again on 1.15 minutes.

Believer - Imagine Dragons has a messier chroma-based self-similarity matrix. A checkerboard pattern can still vaguely be recognized as well as vague diagonal line that indicate something similar plays in two different parts of the song. The matrix is vertically split by a yellow line around 2 minutes in the song which is the short silence before a new chorus. Looking at the timbre-based self-similarity matrix the checkboard pattern is really clear with large blocks for the unique sounds of the chorus and verses.

Hotel California - Original versus Remaster

The chromagram show in yellow the melody line of Hotel California - 2013 Remaster. The melody loops and becomes murkier or clearer depending on the other instruments.

Comparing the 2013 Remaster using Dynamic Time Warping with Hotel California 1976 you’d expect a darker diagonal line along the diagonal of the plot but here it’s absent. We do see a vague dark grid-like pattern over the plot where the darker diagonal paths are most likely the riffs in both songs lining up. The ends seems to be another problem area witch significantly more yellow and interruption of the diagonal grid pattern.

Tempo distribution

Distribution of timbre coefficients

The timbre coefficients for each decade are closely related. All decades have distributions near the same region for each coefficient. Finding features that can reliably split decades are not present. A extremely tiny trends can be seen in most coefficients as for example in the first or sixth coefficients but other than those examples are the timbre coefficients not great features to distinguish the playlist based on them

Led Zeppelin - Stairway to Heaven & Queen - Bohemian Rhapsody

Two iconic rock numbers have interesting tempi changes. Stairway to Heaven has a constantly increasing tempo. Starting around 71 BPM the tempo bumps up to around 82 BPM and continues to increase. At the end of verse 6, or 330 seconds, a transition and solo follow that have a peak BPM of just over 100 BPM.

Bohemian Rhapsody has iconic sections of different genres in the same song. The tempo change that stands out the most is the operatic section with a BPM of 146 starting around 190 seconds and ending around 240 seconds.

Classifying early (60s-80s) and late (90s-10s) era’s of rock